Google Performance Max (PMax) Guide for eCommerce Brands
A practical guide from a specialist eCommerce PPC agency.
Google’s Performance Max (PMax) campaigns are a powerful tool for brands across a wide range of industries.
This guide is designed to help eCommerce brands that are newer to PMax get the most out of this highly automated and versatile campaign type.
What is Performance Max (PMax)?
Quick answer:
Performance Max is a goal-based campaign type within Google Ads that allows you to reach customers across Search, Display, YouTube, Shopping, Gmail, and Discover - all from a single campaign.
Example:
A traditional Search campaign only shows ads when users search specific keywords.
With PMax, Google automatically places your ads across multiple channels to maximise performance based on your goals.
Why Use Performance Max (and When)
PMax is especially valuable for eCommerce brands that sell physical products. It enables you to appear in multiple placements without needing to build and manage separate campaigns for each channel.
Best Practices for Setting Up PMax for eCommerce
We won’t walk through the full setup here, but we’ll share key tips and strategies to get the most out of your campaigns.
Tip 1: Limit Your Products (If You Have a Large Catalogue)
Having hundreds of SKUs is great , but dumping your entire product feed into a PMax campaign can dilute performance.
Start by focusing on your top-performing products that:
- Drive the highest profit margins
- Convert consistently
- Have the highest LTV (lifetime customer value).
This allows Google to build cleaner conversion paths and allocate budget more effectively.
Tip 2: Monitor Where PMax Is Spending Budget (Placement Optimisation)
PMax campaigns automatically spread your budget across placements like Search, Shopping, Display, YouTube, and more. That flexibility is powerful, but only if it’s working in your favour.
If most of your budget is going to Display placements with low purchase intent, you may be missing out on higher-ROAS channels like Shopping.
A great tool you can use to monitor this is the PMax script by Mike Rhodes.
Once you know where it’s spending, you can tweak your asset groups (especially creative and copy) to steer budget toward more profitable placements.
Tip 3: Optimise for the Right Conversion Events
Google’s machine learning follows your signals. So, the events you choose to optimise for, and your bidding strategy matter a lot.
If you’re optimising for events like “Contact” or “Phone Call,” Google may shift more budget toward lower-intent placements like Display, since those conversions are easier to generate.
Instead, for eCommerce, focus on purchase events as your primary conversion goal. This ensures the algorithm is learning from high-value actions.
Also consider which bidding strategy suits your goals:
- Maximise Conversions
(Good when you’re starting out and don’t have much campaign data). - Target CPA
(Switch to this once the campaign has a good volume of conversions). - Maximise Conversion Value
(Good if you want to optimise towards higher average order value purchases). - Target ROAS (tROAS)
(Use this to help stabilise your average returns once the campaign has a good volume of conversions).
Tip 4: Ensure Tracking Is 100% Set Up
As with any Google PPC campaign, it’s critical to give the system the right data.
This means having enhanced conversions setup and all other relevant requirements such as consent mode v2.
If you don’t have the right signals going into the platform, Google cannot optimise your campaigns effectively.
TL;DR – PMax for eCommerce
Performance Max is a campaign type that shows your ads across Google’s entire inventory (Search, Shopping, YouTube, Display, Gmail, Discover).
Quick Recap:
- Tip 1: Limit your product feed to top sellers if you have a large SKU list.
- Tip 2: Track where your budget is going, and refine your assets to guide spend to profitable placements.
- Tip 3: Optimise for purchase events (not softer conversions) to improve ROAS.
- Tip 4: Ensure tracking is set up correctly.